This article briefly presents the different models for hydrogen entry in iron from acid aqueous solutions, namely through an adsorption step mechanism and the direct entry mechanism.

Charging experiments were performed on ARMCO iron membranes using a Devanathan-Stachurski cell in deaerated solutions of various pH and H2S contents at corrosion potential. The influence of these parameters was evaluated. It was observed for 0.5 mm thick membranes that the hydrogen permeation is at a constant flux, as recently observed by other researchers and not at constant concentration.

It was demonstrated that at low current it was not possible to conclude of the mechanism, because both lead to linear relation between permeation current and cathodic current.

The hydrogen permeation was also investigated for large cathodic overvoltages and various media at different pH (4 and 13). Finally, some practical considerations for severity of SSC tests are discussed.

Subject
Hydrogen permeation, Fluxes, Hydrogen concentration, Corrosion currents, Corrosion rate, Iron, Permeation current, Acidity, Permeation, Constants, Steel, Corrosion potential, Hydrogen
Keywords:
Hydrogen absorption, Hydrogen embrittlement, Hydrogen permeation model, H2S, Sulphide stress cracking
© 2004 Association for Materials Protection and Performance (AMPP). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
2004
Association for Materials Protection and Performance (AMPP)
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